Identify the domain and range of the given function. Enter your answers using interval notation. Also, identify the equation of its horizontal asymptote.
a) Domain: ( (-[infinity], [infinity]) ), Range: ( (-[infinity], [infinity]) ), Horizontal asymptote: ( y = 0 )
b) Domain: ( (-[infinity], 0] ), Range: ( (-[infinity], [infinity]) ), Horizontal asymptote: ( y = 0 )
c) Domain: ( (-[infinity], [infinity]) ), Range: ( (-[infinity], [infinity]) ), Horizontal asymptote: ( y = 2 )
d) Domain: ( (0, [infinity]) ), Range: ( (0, [infinity]) ), Horizontal asymptote: ( y = 0 )